O-Ring No Metal Detectable No X-Ray Detectable System of Measurement Inch Cross Section Shape Round O-Ring Material Buna N Durometer (Hardness) Rating Very Hard Nominal Inside Dia 5/16 in Nominal Width 3/32 in Actual Inside Dia 0.299 in Actual Width 0.103 in Dash Number 109 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 1/2 in Actual Outside Dia 0.505 in FDA Approved No Package Quantity 50